We’ve all been guilty of Facebook stalking – looking up strangers who we might be meeting face-to-face soon – a blind date, a potential employee, or even the friend of a friend. It’s supposed to make us feel a little more comfortable and prepared when the real-life meeting actually takes place.

Or maybe not. Especially if you have mild social anxiety. In a study involving female college students, Shannon Rauch and her colleagues found that surprisingly, a Facebook introduction tended to make some people more nervous during the face-to-face meeting.

Rauch, an assistant professor of psychology at Benedictine University in Arizona, and her colleagues recruited 26 undergraduates and asked them to take a social anxiety test. A week later, the team invited to participants to what they called a facial recognition test – the students were hooked up to a monitor to measure changes in how well the skin in their hands conducted electricity (the more aroused a person is, the better the skin conducts electrical signals) while they looked at either pictures of people or actual people in the testing room. There were four groups: one saw only a person’s Facebook profile page, another saw only a person in the room, another saw a person’s Facebook profile and then saw the person in the room, while the final group saw a person in the room and then perused her Facebook page. For the live encounters, both the participants and the visiting person were told not to interact or talk to one another, which limited the experience to just being in the person’s company.

The students who first viewed a person’s Facebook profile and then saw the person in the room showed higher arousal scores than those who simply saw the person, without a prefacing Facebook encounter. That surprised Rauch a bit, since most of the data on digital social interaction suggested the online experience could help to calm the anxiety of meeting someone for the first time in person. “Intuitively we all thought it should help to pave the way a little bit,” she says of her findings, published in the journal Cyberpsychology, Behavior and Social Networking.

Instead, the Facebook priming made them more aroused. Rauch says the study just measured arousal, and not levels of stress hormones so she can’t say whether the participants were more anxious. It’s possible, for example, that the students were just more excited by the face-to-face encounter, which is a natural response to seeing someone. But Rauch believes that the change was more negative than positive, since it raised arousal, instead of calming it, which is what a more positive effect of the Facebook encounter would have had.

The effect was strongest among those who scored higher on the social anxiety test, which suggests that the real-life encounter was still more arousing than the online one – something that previous studies have shown. Online interactions may feel more safe and comforting to those with social anxiety, since they have more control over the situation.

The results go against the idea that online experiences can be a helpful way for some people with social anxiety disorders to gradually get used to real life encounters. “If your goal is to calm yourself for the face-to-face encounter, Facebook is probably not the best strategy,” says Rauch.

Why? The initial online experience could start a process of rumination that leads to expectations and comparisons that the real life encounter may not meet or fulfill. That’s supported by a growing number of studies that show regular Facebook users don’t feel good about themselves, because they are constantly comparing themselves to their peers – on looks, accomplishments and goals.

Rauch hopes the work starts to question conventional wisdom about how social media helps, or even harms, social connections, and plans to study the effect in more detail, by giving participants more choice and control over the real-life interaction, and giving them more opportunity to plan the encounters. “We’d like to start using physiological data to start challenging notions of how social media affects social connections,” she says.